Integrated circuits typically include signal paths, or “conductors” upon which signals are transmitted. Signals take a finite amount of time to propagate along a conductor. This time is referred to herein as “propagation delay.” Propagation delay of a conductor may be influenced by many factors. For example, propagation delays may be influenced by the physical dimensions of a conductor, electrical properties of the conductor, environmental factors such as temperature, and the like.
FIG. 1 shows a prior art integrated circuit. Integrated circuit 100 includes sequential elements 110 and 112 coupled by conductor 114. Clock distribution circuit 120 provides a clock signal CLK1 to sequential element 110, and also provides a clock signal CLK2 to sequential element 112. Clock distribution circuit 120 typically includes matched circuits to distribute CLK1 and CLK2 as closely phase-matched as possible.
Propagation delay “tpd” describes the amount of time it takes for a signal to propagate along conductor 114 between sequential element 110 and sequential element 112. Synchronous communications can take place between sequential element 110 and sequential element 112 as long as the propagation delay of conductor 114 is less than the period of clock signals CLK1 and CLK2. As clock signals increase in frequency, and as propagation delays increase due to larger integrated circuits, propagation delays may become larger than the clock period, introducing errors in the synchronous communications.